The present invention relates to an interposer for electrically testing a ceramic substrate, and more particularly, relates to an interposer used to maintain temporary contact between a ceramic substrate and a test bed comprising so-called pogo pin contactors.
A ceramic substrate is used in the electronics industry for carrying at least one semiconductor device. Usually there are mounted a plurality of semiconductor devices on the ceramic substrate. A ceramic substrate usually consists of a plurality of insulative layers containing wiring patterns and vias which connect between the layers. In totality, the wiring patterns and vias form wiring nets and, in use, provide electrical contact between the various semiconductor devices and between the various semiconductor devices and the next level of packaging.
Before mounting the semiconductor devices, it is necessary to ensure that all the wiring nets are insulated from each other and have the proper electrical continuity.
Accordingly, it is necessary to have a temporary method of connecting the ceramic substrate with a test bed, which for the purposes of the present invention contains a plurality of pogo pin contactors. The ceramic substrate contains input/output devices which connect to the next level of packaging but are also used for testing the wiring nets of the ceramic substrate. The input/output devices may be, for example, pads, pins or solder balls. In the test bed, the pogo pin contactors have a single spring loaded tip which eventually must make electrical contact with the input/output devices of the ceramic substrate. Pogo pins may have single or double spring loaded tips.
Pogo pins and pogo pin contactors are generic for the class of telescoping, spring-loaded connecting pins. Pogo pins and pogo pin contactors are commercially available from companies such as Interconnect Devices, Inc., Kansas City, Kans. Whenever pogo pins and pogo pin contactors are used throughout this application, it should be understood that telescoping, spring-loaded connecting pins are intended.
Too, the input/output devices of the ceramic substrate may have a different grid than the test bed pogo pin contactors so it is necessary to have a grid transformer to accommodate the various differences in grids.
Various devices have been proposed for making nonpermanent connections between electronic devices.
Kato et al. U.S. Pat. No. 5,727,954, the disclosure of which is incorporated by reference herein, discloses an interposer for making connection between an integrated circuit device and a substrate. The interposer includes spring-loaded contact pins for making the connection.
Sayre et al. U.S. Pat. No. 5,773,988, the disclosure of which is incorporated by reference herein, discloses a hybrid test fixture in which various spring loaded probes, guide plates and wires are utilized to make connection between a test board and a printed circuit board.
Antonello et al. U.S. Pat. No. 5,767,692, the disclosure of which is incorporated by reference herein, discloses a test fixture consisting of plates and long needles for converting between the test grid and the grid of the printed circuit board under test.
Kimura et al. U.S. Pat. No. 5,574,382, the disclosure of which is incorporated by reference herein, discloses an interposer consisting of spring loaded needles for testing a printed circuit board. Also disclosed is a pitch-converting board for converting between the pitch of the printed circuit board contacts under test and the contacts of the test board.
In view of the above, it is a purpose of the present invention to have an interposer for temporarily connecting a ceramic substrate to a test bed for electrical testing.
It is another purpose of the present invention to have an interposer for temporarily connecting a ceramic substrate to a test bed for electrical testing and which will also accommodate a different grid between the ceramic substrate and the test bed.